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    <script>
      /*   //字符串+数字  结果就等于  张三20
         console.log('张三'+20);
         console.log('张三'+20+'岁');
         var age=20;
         console.log('张三 '+age);   //输出到控制台的都是变量在内存中保存的值 */

         var str1 = 'aa"bb"cc';   // 可以用''包含""
         var str2 = "aa'bb'cc";  // 也可以用"" 包含''
         console.log(str1);
         console.log(str2);
         
         var str3='abb'+'ab'+'ab"ss"cc'+'cc'
         var str4="ab'sa'cd"
    </script>
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